Identification of a methyl jasmonate-responsive domain in the soybean vspB promoter

Abstract

Soybean vspB encodes a highly expressed vegetative storage protein-acid phosphatase. In soybean, vspB expression is stimulated by methyl jasmonate (MeJA) and sugars. The vspB promoter was studied by transforming tobacco with fusions of 5′ noncoding vspB DNA and the gene encoding β-glucuronidase (GUS). Constructs containing 833 bp of vspB 5′ DNA showed high expression of GUS in stems, leaf veins and trichomes, sepals, and pollen. Sucrose (0.2 M) and MeJA (10-5 M) increased gene expression when applied to leaf tissue. Deletion of the region -787 to -520 with respect to the transcription initiation site rendered the vspB promoter noninducible by MeJA but still sucrose responsive. This result indicates that DNA elements capable of modulating vspB by MeJA can be separated from carbon response elements. Further 5′ end deletion from -520 to -403 or 3′ end deletion from -165 to -289 removed DNA sequences involved in carbon modulation of gene expression. A DNA domain that mediates the MeJA response was further localized to a 50-bp region between -535 and -585. This domain when fused to a cauliflower mosaic virus (CaMV) 35S truncated (-88) promoter makes the CaMV promoter responsive to MeJA. The MeJA-responsive domain contains a G-box motif (CACGTG) and a C-rich sequence. A similar 50-bp DNA region is present in the putative promoter of vspA. Related sequences are located in a wound- and MeJA-responsive domain of the proteinase inhibitor II gene and a UV-responsive promoter domain of chs, the gene encoding chalcone synthase that is also responsive to MeJA.